Wendi Deng, the wife of the media mogul Rupert Murdoch, and Anna Murdoch Mann, his former wife, have a seemingly cordial relationship.
They see each other at family gatherings, like the weddings of Anna and Rupert's three adult children, and the christening of grandchildren, people who are close to the family say. Rupert Murdoch's two young children with Ms. Deng, his third wife, play frequently with the grandchildren he shares with Anna Mann, his second wife, who has remarried.
Anna Murdoch Mann, top, in 1998 and Wendi Deng in 1999, with Rupert Murdoch, are looking to secure their children's futures.
But despite these family get-togethers, an underlying tension is growing over eventual control of the News Corporation, the globe-spanning media company that Mr. Murdoch has built over four decades, with Ms. Deng and Mrs. Mann playing crucial roles.
A simmering debate over the trust that owns the family's 28.5 percent voting stake in the News Corporation surfaced with the resignation last week of Lachlan, Mr. Murdoch and Mrs. Mann's elder son, from his job at the News Corporation, where he was seen as a potential successor to his father.
The precipitating reason for Lachlan's departure, he has told several people, was his father's undermining of his position within the company over a long period.
People close to both father and son have also acknowledged, however, that tensions over the trust were a factor, and those tensions stem from the conflicting maternal ambitions of Ms. Deng and Mrs. Mann.
Last year, Mr. Murdoch told his children that he wanted to change the trust to give his two daughters by Ms. Deng, Grace, 3, and Chloe, 2, a greater role in the trust, which currently has an interest in the News Corporation worth $6.1 billion.
But Mr. Murdoch's four adult children - three with Mrs. Mann and one with his first wife - have a say in the trust and are its primary beneficiaries, and they must approve this change.
While the older Murdoch children do not object to their two young half sisters having a greater share in the inheritance, they have balked at giving them an active or voting role in the trust, these people say. One person close to the Murdoch children said Ms. Deng was driving for her children to have equal standing, which Mr. Murdoch denied. A spokesman for Mr. Murdoch said: "It was his decision and it's always been his belief that all his children should share equally."
Yet the terms of Rupert and Anna's 1999 divorce were crafted to prevent Mr. Murdoch from having the power to make such a change, Mrs. Mann's divorce lawyer, Daniel Jaffe, said. "One of the key factors in the divorce negotiations was to assure that they are trustees and nothing can be done without their consent," Mr. Jaffe said in a telephone interview yesterday.
Mr. Murdoch raised the issue of including his youngest daughters in the trust last year at a family meeting in New York, where one person close to the family said the debate was lively. The meeting was linked to moving the News Corporation's domicile from Australia to the United States, which took place last year.
The Murdoch children agreed that the trust could be changed to include their half sisters financially, but objected to their half sisters sharing control of the company, the person said. Since then, Mr. Murdoch has not moved ahead with a formal proposal to change the trust.
Mr. Murdoch and Ms. Deng declined comment, as did Mrs. Mann, the Murdoch children and company spokesmen.
In practical terms, the four Murdoch children's power over the AE Harris Trust gives each of them - Prudence, 46, from Mr. Murdoch's first marriage; and Elisabeth, 36; Lachlan, 33; and James, 32, from his second marriage - the power to appoint a trustee with one vote apiece. Mr. Murdoch has four trustees and votes that are to expire upon his death.
James Murdoch is the only child still active in the company, where he is chief executive of British Sky Broadcasting, the satellite company based in London that is 34 percent owned by the News Corporation. Elisabeth left her job at BSkyB in 2000.
Mr. Murdoch was married to Anna, a former newspaper reporter whom he had met in Australia, for 31 years. Ms. Deng, a native of China who has a master's degree in business administration from Yale, was an executive at the corporation's StarTV division in Hong Kong when she met Mr. Murdoch in the late 1990's.
